Scraper



March 30,1943.

J. H. VYMGKEAN Er AL/ SCRAPER Filed April 17, 1940 Patented Mar. 30,1943 scRArER o John H. McKean-and verett K. McKean, Alvin, Tex.,asslgnors to Stanolind Oil and Gas Com-y i pany, Tulsa, Okla., acorporation oi Delaware application Apri1.17,.194o, .serial Nassopsr 4claims.' (ci. les-1s) This invention relates to scrapers designed toremove .deposits from the interiors ,oitubea pipes l and the like. Moreparticularly it relates to Scrapersl :for the removalof deposits fromwells and still more particularly to Scrapers for the removal oiparafiln and similar deposits -from the tubings of oil wells.

In many different connections deposits are Ibuilt up on the interiors oftubings and similar .conduits and it is often desired to remove thesedeposits. One particularly serious problem of this type exists in oilwells producing certain types of fluids notably crude oil containinglarge amounts oiv wax. As such fluids progress up the tubing of a l wellthe pressure'drops with the result that some of the 'lighterhydrocarbons are vaporized. 'At the same time the temperature is loweredwith the result that waxy materials, commonly known as lparalmandsometimes other materials of an asphaltic or resinous naturev arethrownout and deposited on the walls of the tubing, particularly in theupper sections thereof. These deposits frequently reach such proportionsthat the capacity of the well is seriously reduced and in fact the wellmay completely plug. It has therefore long `been the custom inconnection with Iwells of this sort to remove these deposits by various.means including the use of solvents and the running ci scrapers.

In general the use of solvents for the removal of these deposits has not.been found very satisfac-l tory and, on the other hand, the use o-fscrapers has ybeen found time-consuming and expensivel due to theunsatisfactory devices heretofore used. In general the prior artScrapers have `not been successful in completely and expeditiouslyremoving difcult deposits in a single run. u This is due in largemeasure to the fact that these devices have served only to 'cut groovesor svvaths4 through the parailin without completely' removing it andmuch difficulty/ has been encountered due tothe balling up of thepara-illu above the cutting knives or similar elementsused in the priorart Scrapers.

It is anobject of our invention to provide new and improved Scrapers forrefmdving deposits from tubes and the like. More particularly it is anobject of our invention to provide aA superior scraper 'for removingdeposits from wells and par-v ticularly for removing deposits, such as.parailin from the tubing oi' 'oil wells. A

A more particular object of our lnvention'is to provide a scraper oi thetype -mentionedwhich will completely remove the deposits.l Anotherparticular object of' our invention is to fprovide a scraper which willnot cause hailing up oi' the Also the use oi wire cutting elements madeposit ahead-of the cutting elements and which will, on the otherhand,cut thel deposits completely-free from the tubing and result in theircomplete removal from the well. a

It is also an object of o ur invention to provide a scraper of the typeindicated which has unusual 'structural strength. .Another .object ofour invention is to provide a scraper having cutting elements which willnot be interfered withby the presence of obstructions in thetubing butwhich willpass by such obstructions and, after passing them, return. tothe normal cutting position. w

A further object of our invention 'is to provide ascraper which -willgive minimum interference with the now of uuid, v

Other and moreV detailed objects, advantages' and uses of our inventionwill become apparent as the description thereof proceeds.

. In general we accomplish these objectives by the use of wires ascutting elements and the wires are preferably constructed and arrangedso that they will spring past obstructions and'then return to theirnormal cutting positions. The use' of wi-res is highly advantageous ascompared with Y the use of .cutting knives or similar. cutting elementswhich present large surfaces to the deposit, since the wires reduce thepullnecessary to operate the scraper, thus eliminating the rbreakage ofscraping tools,'and do not cause balling of the par'ain'ahead of thecutting elements. ttes it of using possible to` do away -with thenecessity separate :spring members for the cutting ele-n ments', sincethe cutting element and spring can be made from a single piece of wire.Furthermore, the wire cutters can be so shaped and of suciisize andspacing as to give a scraping action over the complete Isurface oi thetubing without.

4putting any undue strain on the scraper.

Our invention will now be further described in connection wt'ih theaccompanying drawing whichv shows one preferred embodiment therecfand`in Figure la is an elevation partly in section ofv the upper portion ofa scraper in accordance with our invention;

Figure 1b is an elevation partly in section of the lower end oi thissame scraper. the upper end' of' Figure 1b corresponding to the lowerend of Figure la; 1 s

.Figures 2 and 3 are front and side elevations,

respectively, of one of the cutting elements shown;

in the device of Figures Ia and 1b;`

. Figurevfiis a'diagram illustrating one possiblev the form used by andalso through holes 2 e arrangement voi'cutting lelements in the deviceofFigures la and 1b; i 1

Figure 5'is a detail in. elevation showing one of the-- cutting elementsin cutting position; and

Figure 6 is a detail in elevation showing one of lthe cutting elementsin depressedl position, as

when passing 'an obstruction. Our scraping tool as shown is made inthree sections. The top section 2|, in the form in which we hasconstructed it, is about 6 inches long. It is hollow and threaded at itslower end f and through the hollow interior 25'of the. upper section andis knotted below it. a This knot 23 is then drawn up into the uppersection2| where it comes to rest against shoulder 26. 'Iihe centralsection 24 is then screwed onto the upper section 2| and the device isthus -aillxed to the wire line 28 and is ready to runin the conventionalmannel'.

The middle section 24 is a steel shaft which, in us,'is about 4 feetlong. 'I'he principal purpose of-this section is to give the tool weightwhich is of advantage in spudding cover the complete internalcircumference of the tubing. Thel length of the cutting elements ispreferably such as to give about 11g inch clearance with the internalwalls of the tubing when the cutting element is standing straightoutwardly.

As seen in Figure 1b the lower end 4| of our cutting tool is preferablytapered to assist in the insertion of the tool into the parailinedtubing.

It is preferableto arrange the cutting elements in opposed pairs so asto avoid any tendency for the cutting action to give unbalanced forces.Thus in the form shown in Figure 1b the two' lowermost cutters arearranged 180 apart, making one of the opposed pairs.

Figure 4 illustrates diagrammatically one arrangement of these cuttingelements. 'Ihe 10W- ermost cutting element is numbered I and thenext'higher` one is numbered 2 and so on to the uppermost one .which isnumbered I6. The

' positions of the arrows in Figure 4 shows the. cirit into the holethrough the'parafilned section of the tubing. Obviously if the tool isotherwise sufficiently heavy this section can be omitted and it isalsopossible, of course, to use .a weighted section below rather thanabove the cutting section.

At the lower end or the central threaded joint tions 2|- and 24, lattached to the lower or cutting section 3|.

Near its upper end section '3| carries a ilat portion 32 which can beused ,in handling this section, for instance, by a wrench or the like.

The cutters 33 carried by this bottom section 3| are outline cutters andare made of tempered spring steel wire. `These cutters are placed inkeyways 34 and are keyedin place by pins 35 section 24 is a.

30, similar to that between sec-l by whichthis central section iscumferential spacing of these numbered cutters. l

Thus, the third cutting element from the bottom is spaced 221/2 from therst, the fth is spaced 221A.; from the third, etc. Figure 1b shows onlytwo of the eight opposed pairs of cutting elements, these pairs beingmade up of the rst and second and ninth and tenth cutting elementsdenoted 331, 332, 33 and 331 respectively. Thus the cutting elements arespaced both longitudinally' and circumferentially so as to give completecoverage, great structural strength, and balanced forces.

From the preceding description of our device its operation will largelybe apparent.. The device is dropped into a Well on wire line 28 throughthe para'ined section of the tubing, the cutters 33 being forced intothe position shown in Figure 1b by contact with the deposit. When thetool has passed below the parafiined section of the tubing, the cuttingelements 33 will fall outwardl ly until heels 39 encounter the bases ofkeyways passing through holes in the walls of the keyways 33 (Figure 3)inthe cutting elements 33. It will be noted that the key- Ways do notpass completely through the body of the tool as in some prior artdevices .and we thus obtain improved structural strength.

As seen in Figures 2 and 3, each' of the cutters 33 are preferablyshaped from a single piece 'of wire which is bent to give' a dat outlinecutting head 31 and to form an opening or loop. adjacent the cuttingedge of the cutter, -a spring section 33 (defining aperture 33) and ashort projecting heel 39. The angle portion 31 of cutter and the heel 33is preferably about 90 or slightly more, depending in part on the shapeof the back wallot keyways 34 against which heels 33 rest. In the formwhich we have l used, the diameter of the tool shaft in alll three inchandthe width of the outline 1/2 inch, the cutters if inch tempered areused in such numas to cut through the between the outline head aroundthe m- 34 at which point the cutter heads 31 will stand horizontally orpreferably pointed upwardly at a slight angle as shown in Figure 5. `Ifgravity should not cause thevcutting elements to assume e this position,they will assume it when their leo upper and outer edges encounter thesurface of the paraffin as the tool is pulled upward since it will benoted that the'se. upper and outer edges project beyond the keyways andare exposed to irictional contact with the paraln. 'I'he result is thatduring the upward course of the tool the outline cutters stand out andeach one cuts away its section of the parailin 42 from the tubing 43(Figure 5) thus making it possible for the upilouiring oil todisintegrate and remove the depos t.

tion 43 on tubing 43 (Figure 6) ,it springs down- Figure 6) untu theobstruction is passed, artrwhichthe spring action of the wire forces thecutter back to its cutting position (Figure 5).

Actual experience has shown Athat even in extremely badly paralned wellsthe cutting tooll or our invention permits the removal oi' the paramnfar more completely and expeditiously than 'do the Scrapers heretoforeused. The wire out ting elements not only give complete cutting but Whena cutting element encounters an obstruc-l prevent balling and unduefrictlonal resistance because the parailin, after having been cut away.

from the tubing,l can pass through the loop or opening in the cutter, asshown in Figures 5 and 6,'and consequently give minimum interferencewith the oil passing upwardly through the weil, which, in turn, assistsin the removal of the paraln deposit.

1 Our scraper and modifications of it which will occur to 'those skilledinthe art can likewise be used in scraping oil pipe lines which`frequently contain parailinic or other deposits.

While we have described our invention in connection with a specificembodiment thereof, it is' to be understood that this is by way ofillustration and not lby way of limitation and that we do4 not mean tobe restricted thereto except as indicated in `themzipended claims.

Weclaim: 1. A scraper for removing parailin deposits and the like fromthe interior of aconduit, comprising a body portion having a pluralityof keyways', an outline cutter mounted in each of said keyways, each ofsaid outline cutters comprising a 'T wire outline cutting head having acutting edge formed as a loop and a portion Aadapted to hold said headyieldingly in cutting position.

2. A scraper according to claim 1 in which said outline cutters areseparated longitudinally -from each other on saidbody portion and alsoplaced circumferentially on said body portion to cover substantially thewhole surface of the conduit to be scraped. y

3. A scraper for removing parailln deposits ann the like from theinterior of a conduit, comprising a body portion havinga plurality ofkeyways, an outline cutterwrnounted in each of said keyways, each ofsaid outline cutters comprising a.

wire outline cutting head having a cutting edge formed as a loop. a'spring portion integral therewith and a heel portion integral with saidspring` portion adapted to cooperate with one of said'- keyways to holdsaid head yieldingly in cutting position. A

4. A scraper according to claim l in which said outline cutters aremounted in said keyways by means of pins passing through said springportion.V

JOHN H. MCKEAN. K. MCKEAN. v

